Quantitative analysis of overnight sleep spindles was performed in 14 patients with primary generalized torsion dystonia, 10 patients with secondary torsion dystonia, 10 normal subjects, and 39 patients with other neurological disorders. Only 4 patients with torsion dystonia had increased numbers of sleep spindles, and only one of these had sleep spindles of an abnormal amplitude or duration. Sleep spindle abnormalities do not appear to be common in torsion dystonia, and are unlikely to be of pathophysiological significance in this condition.